[Imaging diagnosis of genitourinary tract tumors]

Recent advance of imaging technique have brought great advantages for management of genitourinary tract tumors. We described few examples of changes in this field from our experience. Many asymptomatic masses are discovered in the kidney and adrenal gland associated with wide clinical application of CT and US. In the kidney, the greater part of incidental masses are renal cell carcinomas (RCC) and the rate of such cases has been increasing. When small RCC is diagnosed without any clinical symptoms, better survival would be expected. Many adrenal incidental mass are also discovered by routine use of CT for abdominal workup. Since greater part of these masses are benign nonfunctioning adenomas, correct diagnosis should be made in order to avoid inappropriate surgery. Rapid development of MR also resulted in some changes in the diagnosis of urinary tract tumors. However, MR cannot be used as a screening method. For staging of RCC, intravascular or adjacent organ invasion was well determined with MR compared with CT. Differentiation of adrenal carcinomas from nonfunctioning adenomas is suggested by the difference of signal intensity on T2 weighted images. Fast spin echo scan with GD-DTPA enhancement is new MRI technique separating bladder mucosal layer from muscle layer as hyper-intensity area. Using this method, diagnostic accuracy of deep muscle invasion for bladder tumor would be improved.